The applicant of the present invention has proposed a pipe joint having a construction in which; in a pipe joint having a C-shaped fastening ring, the fastening ring is provided with a bolt member in a direction approximate to tangent line having a worm wheel portion on one end and a nut to be screwed to the bolt, the worm engaged to the worm wheel portion is driven by electric tools to rotate, and the fastening ring is diminished in diameter by screwing and fastening the nut and the bolt (refer to patent document 1, for example).
However, in the pipe joint described above, frictional resistance of rotation on the screwed portion is large because the fastening force on the bolt member and the nut member by screwing is extremely large, and frictional resistance on an engagement portion of the worm wheel and the worm is extremely large. Therefore, when used for a PEX pipe (bridged polyethylene pipe) of large diameter and thickness, fastening is difficult or impossible in some cases.